regex.cpp

#include <iostream>
#include <boost/regex.hpp>

int main()
{
	std::string file_path = "/foo/bar/bunny.obj";
	std::string type = "unknown";
	boost::regex rx_find_extension("([^\\.]+)$");
	boost::smatch result;
	if ( boost::regex_match( file_path, result, rx_find_extension ) )
	{
		type = result.str(1);
	}

	std::cout << type << std::endl;
}

// output
unknown